The present invention pertains generally to heat transfer and in particular to heat transfer through the formation and decomposition of metal hydrides.
Presently several devices, often referred to as heat pumps, are utilized to transfer heat. They can be classified into two types. The first type of device operates by first compressing a fluid which at this step is in the gaseous phase. The pressurized gas is then passed through a heat exchanger and cooled by roomside air. The fluid changes state with the loss of heat and becomes a liquid. The heat of vaporization is thus transferred to an environment. The liquid then passes out of the heat exchanger, through an expander and into another heat exchanger. At this lower pressure the fluid has the tendency to boil with the addition of low temperature heat. Air from another environment supplies this heat through the heat exchanger and thus transforms the fluid to a gas again, the gas then returns to the compressor.
The other type of device is referred to as an absorption heat pump. This type like the first type utilizes a compression-vaporization cycle to transfer heat. The difference between the two types reside in the means for effecting compression of the vapor. With the compressor type of device, a mechanical compressor is used, whereas an absorption type of heat pump accomplishes compression by contacting the vapor with a medium which unites with the vapor.
The performance of heat pumps of either type are evaluated in terms of the coefficient of performance (C.O.P.). As a refrigerator the COP of a heat pump is calculated by C.O.P. = refrigerating effect/heat of compression. As a heater, the coefficient of performance for a heat pump is calculated by C.O.P. = heat delivered/heat of compression